Summary Adoption of New Accounting Standard Impact on Income Statement (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Net sales	$ 2,033.0	$ 1,952.6	$ 6,485.4	$ 5,978.1
Type of Revenue [Extensible List]	us-gaap:ProductMember	us-gaap:ProductMember	us-gaap:ProductMember	us-gaap:ProductMember
Cost of sales	$ (1,646.9)	$ (1,557.7)	$ (5,199.3)	$ (4,739.2)
Type of Cost, Good or Service [Extensible List]	us-gaap:ProductMember	us-gaap:ProductMember	us-gaap:ProductMember	us-gaap:ProductMember
Operating income	$ 192.5	$ 167.2	$ 665.0	$ 609.3
ASU 2014-09
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Net sales	$ 2,033.0		$ 6,485.4
Type of Revenue [Extensible List]	us-gaap:ProductMember		us-gaap:ProductMember
Cost of sales	$ (1,646.9)		$ (5,199.3)
Type of Cost, Good or Service [Extensible List]	us-gaap:ProductMember		us-gaap:ProductMember
Operating income	$ 192.5		$ 665.0
ASU 2014-09 | Balances without adoption of ASC 606
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Net sales	$ 2,032.4		$ 6,481.2
Type of Revenue [Extensible List]	us-gaap:ProductMember		us-gaap:ProductMember
Cost of sales	$ (1,646.5)		$ (5,195.7)
Type of Cost, Good or Service [Extensible List]	us-gaap:ProductMember		us-gaap:ProductMember
Operating income	$ 192.5		$ 664.3
ASU 2014-09 | Effect of Changes
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Net sales	$ 0.6		$ 4.2
Type of Revenue [Extensible List]	us-gaap:ProductMember		us-gaap:ProductMember
Cost of sales	$ (0.4)		$ (3.6)
Type of Cost, Good or Service [Extensible List]	us-gaap:ProductMember		us-gaap:ProductMember
Operating income	$ 0.0		$ 0.7